A conventional steering column is installed and tilted in a tilting apparatus. The tilting apparatus typically includes a tilt bracket which supports the column tube of the steering column, a mounting bracket which is installed in a predetermined portion of a vehicle and supports the tilt bracket such that the tilt bracket is movable up and down, and an operating lever which is mounted to the tilt bracket to fix the position of the tilt bracket relative to the mounting bracket. Thus, a user may move the tilt bracket for supporting the column tube to a predetermined position of the mounting bracket by operating the operating lever, so as to set the tilt bracket.
However, when impact or vibration is applied to the vehicle in the above structure, the tilt bracket for supporting the heavy column tube deviates from the set position while sliding from the mounting bracket. In this case, there is a problem in that the user operates the operating lever again to change the position of the tilt bracket.
Korean Patent No. 10-0561086 (hereinafter, referred to as “Prior Document”) discloses a new apparatus for tilting a steering column in order to resolve the above problem.
The apparatus in the prior document includes a fixing part in which a mounting bracket is fixed to a predetermined portion of a vehicle, first and second side parts which respectively extend downward from both ends of the fixing parts, a gear guide groove which is formed in the first side part while having a gear formed on the inner peripheral surface thereof, and a slide guide groove which is formed in the second side part and corresponds to the gear guide groove.
In addition, a tilt bracket includes a tilt shaft which passes through the gear guide groove and the slide guide groove and has a brake gear formed on the outer peripheral surface thereof, the brake gear engaging with the gear guide groove, and a shaft movement part which axially moves the tilt shaft such that the brake gear is selectively engaged with the gear guide groove. An operating lever includes a lever shaft part which is organically coupled to the shaft movement part so as to axially move the tilt shaft, and a lever part which extends from the lever shaft part and is pushed by a user.
Particularly, the shaft movement part includes a first cam bush which is fixed to the first side part while the tilt shaft passing through the gear guide groove passes through the first cam bush, a second cam bush through which the tilt shaft passes in the state in which it is pressed against the first cam bush, a nut which is coupled to the tilt shaft passing through the slide guide groove, and a Belleville spring which is installed between the nut and the second side part. The first and second cam bushes have first and second slopes which are formed on the facing surfaces thereof and are inclined to one side. The tilt shaft passing through the second cam bush and the second cam bush is fixed to the lever shaft part.
In the prior document that discloses the apparatus having the above configuration, when the driver changes the position of a steering wheel by operating the lever part of the operating lever, the first cam bush is close to the second cam bush by the first and second slopes, so that the tilt shaft, which is elastically biased by the Belleville spring, moves to the Belleville spring, and the brake gear is disengaged from the gear guide groove. In this state, the user may operate such that the steering column is located at a specific position by moving the tilt bracket in upward and downward directions relative to the mounting bracket.
However, in the prior document, the first and second cam bushes have to be separately manufactured in a special form that has the first and second slopes, and the brake gear may not be smoothly engaged with the gear guide groove, due to the complicated engagement structure thereof, when the distance between the first and second cam bushes is increased and then decreased. For this reason, consumers may be adversely affected by faulty operation, and the emotional quality of product may be deteriorated due to occurrence of dull mechanical friction noise.